1. Field of the Invention
The present invention relates to a driving support apparatus.
2. Description of the Related Art
Conventionally, there have been proposed many systems that provide information to drivers by detecting obstacles or preceding vehicles existing around own vehicles or by detecting in-lane positions of the own vehicles. There have also been proposed many systems that aid driving operations of drivers or perform the driving operations in place of drivers on the basis of detection results. The oversight or misidentification of detection targets that occurs in these systems has become a large problem because it becomes impossible to ensure that sufficient convenience and safety are provided by the systems for the drivers. Here, the term xe2x80x9coversightxe2x80x9d is defined as a situation where xe2x80x9cno obstacle is detected although there exists any dangerous target objectxe2x80x9d, while the term xe2x80x9cmisidentificationxe2x80x9d is defined as a situation where xe2x80x9can obstacle is detected although there exists no dangerous target objectxe2x80x9d.
That is, if obstacle detection sensitivity is enhanced in order to circumvent the xe2x80x9coversightxe2x80x9d for the sake of enhancing the safety, there frequently occurs the xe2x80x9cmisidentificationxe2x80x9d. Consequently, this enhancement of the obstacle detection sensitivity is not acceptable from the viewpoint of practical use because the driver""s convenience provided by the systems is reduced. Also, if the obstacle detection sensitivity is conversely reduced in order to suppress the xe2x80x9cmisidentificationxe2x80x9d, there is reduced the safety, which renders the systems useless.
In view of these problems, there have been proposed several apparatuses that reduce the frequency of occurrence of the oversight and misidentification. In JP 06-148328 A titled xe2x80x9cObstacle Recognition Apparatus for Vehiclexe2x80x9d, for instance, there is proposed an apparatus that divides an area around a vehicle into small regions, stores a probability value expressing at least one of the probability of the presence of an obstacle and the probability of the absence of an obstacle for each small region, and performs totalizing to improve the reliability of detection, wherein the reliability is further improved by updating the stored value on the basis of the correspondences between (i) the small regions before displacement of the vehicle and a change of an azimuth angle and (ii) the small regions after the displacement and change.
Also, in JP 10-112000 A titled xe2x80x9cObstacle Recognition Apparatusxe2x80x9d, there is proposed an obstacle recognition apparatus that is provided with a plurality of sensor units and enhances the reliability of detection using a means for judging to which one of three region evaluations of xe2x80x9cpresence of obstaclexe2x80x9d, xe2x80x9cabsence of obstaclexe2x80x9d, and xe2x80x9cambiguousxe2x80x9d each point within a measurement range of each sensor unit belongs and a means for calculating the degree of sureness of the judgment result, wherein the merger of detection results of the plurality of sensor units is easily performed using the calculated degree of sureness.
Further, in JP 2000-180537 A titled xe2x80x9cMethod for Identifying Target to be Controlled of Scan-Type Radarxe2x80x9d, there is proposed an intervehicular distance control system whose reliability is improved by obtaining an existence probability value and an own lane probability value in consideration of a detection distance, a positional deviation, the number of detection beams, a relative speed, and the state of an object (whether the object is stationary or moving), and by judging whether the detected object is a preceding vehicle that will become a control target using the obtained probability values.
Even with the proposed techniques described above, however, it is impossible to completely eliminate the occurrence of the oversight and misidentification using currently available techniques. On the other hand, even if there is provided information whose contents are incorrect because there occurs oversight or misidentification of a detection means in these systems that provide information, aid a driving operation, or perform a driving operation in place of a driver, there is a possibility that a system is realized which provides convenience acceptable to the driver by suppressing the frequency, with which incorrect information is provided, to a certain level.
Also, in the system that aids a driving operation of a driver or performs a driving operation in place of a driver on the basis of a detection result, even if the system does not aid the driving operation or does not perform the driving operation in place of the driver with reliability because there occurs the oversight or misidentification of a detection means, if the degree of danger of a malfunction of the system is sufficiently small and it is possible for the driver to recover the malfunction, there is a possibility that a system is realized which provides safety acceptable to the driver.
That is, even if the occurrence of the oversight and misidentification of a detection means is not completely eliminated, there is a possibility that the system is put to practical use by realizing both of convenience and safety using the system.
By the way, in these systems that provide information, aid a driving operation, or perform a driving operation in place of a driver, the reliability of the provided information, the reliability of an operation performed by the systems to aid a driving operation, or the reliability of an operation performed by the systems to perform a driving operation in place of a driver has a significant meaning for the driver""s convenience provided by the systems.
In a system that detects an obstacle, a vehicle, or the like existing around an own vehicle and provides information to a driver, for instance, even if the information is provided in the same manner as in the case of high reliability although the reliability of the obstacle detection result is low, it is impossible for the driver to know the reliability. Consequently, each time information is provided, the driver is placed in a tense condition because he/she has to worry about an obstacle. As a result, the driver regards this situation as a nuisance. It may be conceived to use a technique with which the problem described above is prevented by refraining from providing information in the case of low reliability, although this technique is not preferable from the viewpoint of ensuring safety.
Also, in a system that aids a driving operation of a driver or performs a driving operation in place of a driver on the basis of a detection result, it is impossible for the driver to know the reliability of the system operation. Consequently, it is required that the driver always maintains a tense condition as a preparation to a malfunction of the system, which impairs the driver""s convenience provided by the system.
The prevent invention has been made in the light of the problems described above, and the object of the present invention is to provide a driving support apparatus that makes it possible to realize a level, which is acceptable to a driver, of each of the convenience and safety provided by the system by using a means that allows the driver to naturally know the reliability of provided information, the reliability of an operation performed by the system to aid a driving operation, and the reliability of an operation performed by the system to perform a driving operation in place of a driver.
A driving support apparatus according to an aspect of the present invention includes: obstacle detecting means for detecting an obstacle around a vehicle; and obstacle information providing means for outputting, by voice, positional information of the obstacle detected by the obstacle detecting means, wherein the obstacle detecting means includes a function of calculating a reliability indicator value concerning a detection result, and the obstacle information providing means includes obstacle information providing and judging unit that judges switching of contents of voice information to be provided in accordance with magnitude of the reliability indicator value outputted from the obstacle detecting means.
A driving support apparatus according to another aspect of the present invention includes: a preceding vehicle detecting means for detecting a preceding vehicle; an intervehicular distance control means for controlling an intervehicular distance to the preceding vehicle detected by the preceding vehicle detecting means; a function of calculating a reliability indicator value concerning a detection result of the preceding vehicle detecting means; and obstacle information providing means for providing voice information for calling driver""s attention when the reliability indicator value changes from a state where the reliability indicator value is larger than a preset threshold value to a state where the reliability indicator value is smaller than the preset threshold value.
A driving support apparatus according to still another aspect of the present invention includes: in-lane position detecting means for detecting an in-lane position of an own vehicle; steering control means for performing control for keeping in-lane traveling on the basis of a detection result concerning the in-lane position detected by the in-lane position detecting means; a function of calculating a reliability indicator value concerning the detection result of the in-lane position detecting means; and obstacle information providing means for providing voice information for calling driver""s attention when the reliability indicator value changes from a state where the reliability indicator value is larger than a preset threshold value to a state where the reliability indicator value is smaller than the preset threshold value.